Due to the phagocytosis of leucocytes, they can eliminate foreign pathogens and safeguard the health of the human body. So, they are called the body defender. There are 4,000-10,000 leucocytes per mm3 in the system of blood circulation of a normal human body. The most important leucocytes are neutrophilic granulocytes having a defensive function, accounting for 50-70% of the total count. Generally, the most frequent and most common leukopenia is neutropenia. When the total leucocyte count is less than 4,000/mm3, body resistance is so low that bacterial infection is easily caused and life is threatened in severe cases. Platelets are one of the blood visible components. The number of platelets in human blood varies greatly, with a normal value of 150,000-300,000/microlitre. Platelets have the functions of stopping bleeding and engulfing viruses, bacteria and other particles, and can nourish and support the capillary endothelial cells to decrease capillary fragility. If the number of platelets significantly decreases or some function disorder occurs, it will lead to a bleeding tendency. Leukopenia and/or thrombocytopenia is common in clinical, including a primary type, a concurrent type and a secondary type. In addition to geneogenous leukopenia and/or thrombocytopenia, there are a variety of causes. Diseases, drugs, radiations, infections, toxins, chemicals, surgical treatments, environmental factors and the like are all likely to cause leukopenia and/or thrombocytopenia. The diseases causing leukopenia and/or thrombocytopenia include hematopoietic system diseases, immune system diseases, infections, systemic lupus erythematosus, allergic shock and thrombocytopenic purpura, etc. Both myeloproliferative disorder and aplastic anemia may be accompanied with leukopenia and/or thrombocytopenia. Bone marrow transplant and liver transplant also directly result in the decrease of leucocytes and/or platelets. Especially for cancer patients, radiotherapy and chemotherapy often cause inhibition of bone marrow hematopoiesis, of which the manifestation is an obvious decrease of peripheral leucocytes and platelets. At present, drugs for treating various types of leukopenia and/or thrombocytopenia are not many yet. The effect of products of genetic engineering, such as granulocyte colony-stimulating factor (GCSF) and granulocyte-macrophage colony-stimulating factor (GMCSF), in increasing leucocyte is remarkable. The Chinese traditional medicine, Sanguisorba Tablet is widely used to increase the number of Leucocytes too, while there are few chemical medicines with significant therapeutic efficacy. Thus, there is a wide need of chemical medicines which can be effective in treating leukopenia and/or thrombocytopenia, convenient to use, easy to control the quality, and easy to obtain by synthesis.
Pentacyclic triterpenes, one type of the naturally distributed triterpenes compounds, are found to have a wide physiological activity. Ursolic acid and oleanolic acid, the most representative compounds thereof, are widely present in the plant kingdom and can be obtained in a large amount. Oleanolic acid has been used for the treatment of liver diseases for many years. In addition to the beneficial effect on liver, both have a variety of other activities according to reports. In the article entitled “Effects of oleanolic acid and ursolic acid on inhibiting tumor growth and enhancing the recovery of hematopoietic system postirradiation in mice (Cancer letter 7-13, 111, 1997)”, Lin et al. studied the effect of ursolic acid and oleanolic acid in inhibiting tumor cell growth and found that ursolic acid and oleanolic acid were effective in increasing leucocytes when they were administrated through abdominal cavity in the doses of 25, 50 and 100 mg/kg, and the effect was obvious in the case of a high dose, wherein ursolic acid was more effective than oleanolic acid. Japanese patent No. JP7048260 also discloses the effect of ursolic acid in increasing erythrocytes and platelets. Chinese patent No. CN03135776 discloses the remarkable effect of triterpenoid saponins in increasing leucocytes and platelets, wherein the triterpenoid saponins are isolated from sanguisorba and mainly have 19-hydroxy ursolic acid (also known as pomolic acid) as an aglycon. Since sanguisorba comprises a series of saponins of such type with similar structures and polarities and with a limited content, it is difficult to separate out and purify the effective monomers in batches for medical use; in addition, the pomolic acid or the aglycon thereof per se is not widely present in natural products, thus it is not easy to obtain them in a large amount in the sight of isolation and extraction; and in the sight of synthesis, it is not easy to obtain 19-hydroxy via simple conversion procedures original from ursolic acid, as a raw material, which is easy to obtain, thus there are certain limitations of its exploitation and utilization.
So far, the use of ursolic acid saponins and oleanolic acid saponins in the preparation of medicaments for increasing leucocytes and/or platelets has not been reported. In the present invention, ursolic acid and oleanolic acid, which are widely distributed in natural products, cheap and easy to get, being creatively used as raw materials, and with the introduction of hydrophilic groups, i.e. monosaccharyls or oligosaccharyls by structural modification, it has been proved that saponins can not only improve the water solubility of the parent nucleus, but also have an activity of remarkably increasing leucocytes and/or platelets by pharmacological tests. Compared to pomolic acid saponin isolated from sanguisorba, the patented compounds not only show up stronger pharmacological activities, but also have advantages of synthesis of simple steps, adaptation to industrial production, low cost and so on.